This invention relates to improvements in the piston drive mechanism of a particular form of an axial-piston engine.
An axial-piston engine is one in which the cylinders are arranged to lie with their axis parallel to the main shaft, instead of normal to it as in an engine having a conventional form of crankshaft.
Axial-piston engines may be classified into two principle generic varieties:
a) Those in which high velocity sliding contact curs directly between the pistons or slippers attached to the pistons, and the main retaining element. Examples of this variety are the Michell Crankless and Dyna-Cam (Herrmann) engines. PA1 b) Those in which a non-rotating element is interposed between the rotating element and the pistons. This non-rotating element is connected to the main shaft by bearings, and its motion can be described as nutation, a wabbling action, by means of which arms at its edge are able to drive the pistons to and fro in a linear motion. Known as wabbler engines, engines of this form nave been undergoing design and development since the early part of the twentieth century.
The wabbler, which is a mechanism for the reversible conversion of linear into rotational motion, may take several forms depending on the nature of the bearing arrangement between it and me main shaft. By the use of a "Z" form of shaft, it is possible to use widely spaced bearings, which can be of either ball or roller type. If a straight shaft is used, the bearing usually takes the form of a thrust bearing, often of the Michell type, between the wabbler and the shaft.